Coal-carbonizing furnace



Mar. 27, 1923.

1,449,591. H. L. DOHERTY.

COAL CAHBONIZING FUHNACE.

FILED SEPT. I. |918. 4 SHEETS-SHEEY l.

Mar. 27, 1923.

H. L. DOHERTY.

COAL CARBQNIZING FURNACE.

4 SHEETS SHEET 2.

FILED SEP?. 7| 191B.

Mar. 27, 1923. 1,449,591. H.L.D0HEH1Y.

COAL CARBONLZING FURNACE.

mio szPTJ. ma. 4 SHEETS-sneu 3.

Mar. 27, 1923.

H. L. DOHERTY. coAL cARBomzmG FURNACE.'

4 SHEET hSHEET 4.

FILED SEPT. l9l8.

Patented Mar. 27, 1923.

UNITED STATES HENRY L. DOHERTY, F NEW YORK, N. Y.

COAL-CARBONIZING FURNACE.

Application led September 7, 1918. Serial No. 253,048.

To all "whom it may concern Be it known that I, HENRY` L. DoHEn'rv, a citizen of the United States, 'residing at New York city, in the county of New York, State of New York, have invented certain new and useful Improvements in Coal-Carbonizing Furnaces; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to coal carbonizing furnaces and more particularly to furnaces for recovering coke and the volatile constitl5 uents of coal as primary reaction products.

At the present time coal is carbonized principally in coke ovens and in externally cated retorts. In the open bee-hive coke oven, sufficient air is admitted to the oven to burn olf the volatile materials of coal and only coke is recovered. In the by-product coke ovens which employ retorts, the coke is produced as a mam product from coal and the volatile materials are recovered as by-products. In a gas bench using either horizontal or vertical retorts, the volatile materials of coal are produced as main products and coke is recovered as a by-product. The coke produced in b V-product ovens dif- *0 fers in physical characteristics from the coke produced in a gas bench due essentially, as usually considered, to the differences in the time periods employed for carbonization. but the gas recovered in the by-product oven 5 has substantially the same constitution as that recovered from the as bench. This gas is composed principal of fixed gases which carry some hydrocarbon vapors, ammonia and heavy tarry products. A very 3 high percentage of the fixed gases and tarry products are secondary reaction products which are produced by the cracking and decomposition of the primary reaction products or oils distilled off from the coal.

i The primary object of the present invention is to provide a carbonization apparatus by which coal is reduced to coke and by which the gaseous and oily products of distillation are recovered with a minimum of I secondary reaction products.

Another object of the invention is to pro vide an apparatus by which coal may be curbonized at reduced partial pressure to lower the temperature at which the volatile i products may be distilled off.

In the preferred form of the invention, the coal is distilled under reduced partial pressure in a vertical shaft furnace by circulating a gaseous heat-transferring medium up through the fuel bed. With coals having a high percentage of volatile materials, a large amount of oil is condensed in the upper portion of the fuel bed and this oil obstructs the passage of the gas through the fuel bed. To overcome this dilliculty, it has been necessary heretofore to mix coke with the coal as it is charged into the furnace to cut down the production of oil and to increase the porosity of the fuel bed, but this use of coke, materiall reduces the ca acity of the furnace for car onizing coal. Fgirther, when large lquantities of oil are condensed in the furnace, the oils drain down toward the highly heated coking zone and may be broken down into fixed carbon and fixed gases.

Accordingly' another object of the invention is to provide an apparatus for carbonizingcoal by which oils as the are condensed and heavy va reus prodiicts may be removed from the urnace to prevent an excess accumulation of the oils and to over come the tendency of the oils to work down into the hot coking zone.

With these and other objects in view, the invention consists in the improved coal carbonizing a paratus hereinafter described and claimed).

The various features of the invention are illustrated in the accompanying drawings, in which, i

Figure 1 is a view in side elevation, illustrating a coal carbonizing furnace and its auxiliary apparatus which embodies the preferred form of the invention;

Fig. 2 is a view in vertical section of the coal carbonizing furnace;

Figs. 3, 4 and 5 are horizontal cross-sectional views of the carbonizing furnace taken respectively on the lines 3-3, 4--4 and 5-5 of Fig. 2;

Fig. 6 is a horizontal sectional view of the carbonizing furnace showing the cokedischarping apparatus in plan;

Fig. is a view in side elevation, partly in section, and Fig. 8 is a view in end elevation of the discharge gate for the coke hoppers and the mechanism for operating the same; y

Fig. 9 is a plan view, and Fig. 1() is a view in vertical section of the coal-charging bucket showin the liquid seal connection of the bucket wit the charging opening of the carbonizing furnace;

Fig. 11 is a bottom plan view. and Fig. 12 is a view in side elevation with parts broken away Showing the fuel-discharging mechanism of the charging bucket.

The coal carbonizing furnace illustrated in the drawings consists of a vertically supported cylindrical gas-tight shell 20 which has a fuel-charging opening 22 at its upper end and coke-removing hoppers 24 and 26 at its lower end. The fueLCharging open ing 22 is always closed by a liquid seal and the coke hoppers 24 and 26 are closed gas-tight by fuel-discharging gates 28 and 30 which may be operated alternately to prevent the escape of gases from the furnace. The fuel is supported in the furnace in a vertical column and continuously advances downwardly, fresh coal being charged through the opening 22 and coke being periodically withdrawn from the hoppers 24 and 26. During the carbonizing opera tion, three distinct zones are maintained in the fuel column,l namely, a localized hot coking zone 32. a coal distilling and lieuting zone 34, and a coke-cooling zone. 86 (see Fig. 2). The heat for maintaining the: carbonization and distillation of the coal is furnished either by a combustion of fuel combustion of a heat-transferring and the different zones in the fuel column are maintained by circulating the heat-transferring gas through the fuel bed coiintercurrent to the advancing movement of the coal. The gas enters the carbonizing furnace through an opening 38 in a comparatively cool state and enters the coke at the base of the fuel column. As the gas passes up through the fuel column, it cools the coke in the cooling zone 36 and carries the heat removed from the coke up to the hot coking zone 32. After the gas passes through the hot coking zone, it advances through the coal-distilling zone and imparts its heat to the coal in the zone 34. At the time the gas leaves the upper part of the fuel column, it is comparatively cold and may be controlled to have any desired temperature to carry out steam or other low boiling vapors from the furnace. The heat-transferring gas, in passing upwardly through the distilling zone 34. progressively heats the coal and practically all of the volatile constituents of the coal are removed before the coal reaches the coking zone The cold fuel at the upper part of the zone 34 acts as a condensing medium for vapors driven off from the coal adjacent the coking zone so that the zone 34 contains a large amount of oil in a liquid state. This oil accumulates at the inner surface of the furnace shell 20 and runs down through a foraminated plate 40 into a tar-collecting chamber 42. Some of the higher boiling vapors and tar formed by the distillation pass out of the zone 34 through an outlet 44 into a collecting chamber 46, and the vapors are removed through an outlet 48. The tar from the collecting chambers 42 and 46 is removed through openings 50 and 52 and discharged through a pipe 54 into a settling tank 56.

The gaseous heat-transferring medium and gases formed by the distillation of the coal pass out of the upper end of the furnace by an opening 58 into a conduit 6() and Join with the gases and vapors from the opening 48 passing through the conduit 62. The vapors from the conduits 60 (Fig. l) and 62 pass through a main 64 into a con denser 66 which removes the oil and tarry products. From the condenser the gases pass into a washer 68 for removing ammonia and then pass through a sulphide purifier 70. From the sulphide purifier the gases flow through a conduit 72 into a gasliolder 74. The tar and oily products from the condenser 66 flow through a cooling coil 76 into a separatin tank 78 and a portion of the condensed oi or water from the separating tank is removed by a pump 80 and circulated by means of a pipe 82 back to the coils of the condenser 66.

rljlie gaseous heat-transferring medium for maintaining the zones in the fuel column in the furnace may be taken from a gas main 83 connecting the scrubber 68 and purifier T() through a valve 84 and thus consist of a fraction of the gas produced in the furnace; or the heat-transferring gas may be intro# duced through a valve 86 from an external source. Blue water gas is well adapted as a heat-transferring gas since this gas is coinposed principal y of hydrogen, carbon dioxide, and carbon monoxide, which ingredients will not be decomposed when passing through the heated coking zone. Further. the constituents of water gas are different from the vapors distilled from the coal and will be added to the coal vapors to decrease the partial ressures in the carbonizing furnace and t us reduce the temperatures at which the volatile constituents will be removed from the coal. The gas from the valves 84 or 86 enters a main 88 and is drawn in through a positive pressure blower 90 and forced into the furnace through a main 100 which is connected to the inlet opening 38.

To support the combustion of the coal in the coking zone, air is carried into the furnace by the gaseous heat-transferring rnedium. The quantity of air is regulated to maintain sufficient oxygen to support combustion but to avoid an execess of air, so that an excess of fuel will not be consumed to produce undesirably high temperatures.

The mixture of air and gaseous heat-transferring medium may form an explosive mixture or a mixture which will back fire if it is not carefully controlled so that the air is mixed with the cold gaseous medium in the main 100. In this way both the gaseous medium and the air will be preheated in passing up through the coke cooling zone to the hot coking zone. The air is controlled by means of a blower 102 which is connected with the main 100 by a pipe 104, (Fig. 1).

By the use of the blowers 90 and 102 and by a regulation of the flow of fuel through the furnace, the three zones in the fuel column may be carefully controlled and the coking zone may be maintained in any desired location. The hot coking zone may be driven upwardly by increasing the velocity of the as passing upwardly through the fuel bedgor by varying the quantity of air introduced into the furnace, or by decreasing the flow of fuel through the furnace. The cokin zone may be driven downwardly in the fue column by decreasing the volicity of the gaseous medium or by varying the quantity of air supplied to the furnace or by increasing the flow of fuel through the furnace. The regulation of these three factors either separately or in combination with one another permits the carbonization of the coal to be accurately controlled. The temperatures of the zones in the fuel column may also be accurately regulated by the blowers to produce a maximum amount of tarry products and a minimum amount of gaseous products.

In order to carbonize coal while maintaining an efficient heat balance in the fuel column, it is necessary to localize the hot coking zone and to keep the upper and lower ends of the fuel column as cool as practicable. Since the heating of the fuel column is accomplished by combustion of fuel of the column or gases present in the coking zone, it is only necessary to provide a refracto lining in the mid portion of the furnace shlell in the. vicinity of the coking zone. To this end a refractory lining 106 (Fig. 2) is mounted in the central portion of the furnace and held in position by a lower plate 108 and an upper plate 110. The lining 106 is practically solid and of sufficient thickness to prevent the leakage of heat through the furnace walls. The inner face of the lining is preferably formed of a high refractory to prevent disintegration due to the temperatures which may be obtained in coking the coal. The lining 106 is preferably made only a sufficient height to include the hot portions of the three zones of the fuel column and to permit the hottest localized coking zone to be shifted up and down in the furnace while controlling the carbonizing operation.

The upper end of the coal-distilling zone and the lower end of the coke-cooling zone project beyond the refractory lining and do not become heated to an excessive temperature. A distinct advantage is gained by holdin the refractory lining in the midzone of t e furnace because it permits the use of steel or metal parts in the upper and lower portions of the furnace and such arts are'more easily and cheaply constructs and are better adapted for the various operations.

The fuel in the coal-distilling zone becomes progressively heated as it advances toward the coal-coking zone and distillation ofthe coal takes place practically throughout the entire length of the zone. The moisture and more volatile vapors are driven olf in the upper portion of the distilling zone and the heavier boilinor vapors are driven oit' as the coal approaches the coke-forming zone. The portion of thefuel in the upper end of the coal-distilling zoneV is sufficiently cold, however, to condense' many of the vapors formed in the lower portion of the distilling zone so that a large quantity of oil condenses in the lfuel body. The oil also condenses around the inner surface of the furnace shell and oil from the coaldrains toward the furnace shell. This oil runs down around the inner surface of the shell more rapidly than through the body of the coal and if it were permltted to Work down Y into the hotter portion of the fuel column, it i would tend to chill the fuel around the periphery of the column. To revent oil from accumulating in the fuel bedp and from workirg down into the cokingzone, it is drawn o through the screen 40 into the collecting chamber 42 (Figs. 2 and 3) where it may be removed from the furnace. The screen 40 consists of a series of segmental p lates'112 which are secured to angular bracketsv 114 attached to the inner surface of the shell 20. The oil-collecting chamber 42 `is formed by a cylindrical plate 116 which is secured to the inner edge of the screen 40 and a partition 118 which is secured between the plate 116 and the inner face of the shell 20. The joints between the partition 118 and the plate 116 and shell 20 are tight to preventl oil from escaping. The fuel banks up on the screen so that a considerable portion of the oil from the body of the coal will reach the chamber 42 in addition to the oil collected on the inner surface of the shell 20. To assist in drawing the oils through the screen 40, a gas outlet 119 is placed in the chamber 42 to permit a. limited circulation of gas through the chamber. The outlet 119 is connected by a conduit 120 with the gas main 64.

The oil collected in the chamber 42 contains a large percentage of the lower boiling point vapors ofthe coal. To collect the higher boiling point vapors, the tar and gascollecting chamber 46 is positioned in the shell adjacentthe hotter portion of the coaldistilling zone. The chamber 46 is formed by the bottom plate 11() at the top of the refractory lining, the partition 118 of the chamber 42 and a cylindrical plate 121 which is secured to the plate 110. The plate 116 is extended downwardly below the partition 118 and the upper end of the plate 121 extends a short distance above the lower end of the plate 116 and is offset outwardly to provide the vapor inlet passa e 44 (Fig. 2). Vith this construction, the eavier boiling vapors formed at the lower end of the coaldistilling zone may pass directly into the collecting chamber 46 and are drawn off through thel outlet 48. Also, the heavier boiling oils which are condensed in the fuel body and which run down toward the coking zone are revaporized and may be collected in the chamber 46. Since the collecting chamber 46 is at the upper end of the refractory lining and close to the hot coking zone, the temperature of the chamber will be comparatively .high and therefore the majority of the oily vapors may be drawn off through the outlet 48. The heavier oils and tars which condense and collect in the chamber 46 are removed through the outlet 52.

The heavy oil vapors removed through the chamber 46 and the oils collected in the chamber 42, maintain the fuel in the coalcarbonizing zone in a comparatively open porous state so that the resistance to the passage of the heat-transferrin gas and thc gas formed in carbonizing t e coal is comparatively low. For this reason, certain types of coal may be carbonized without the admixture of coke to maintain the porosity. and the amount of coke which must be added to coals having a high percentage 0f volatile materials is comparatively low. By drawing oil' a portion of the oil vapors, the amount of oil running back toward the coking zone is reduced so that the remaining oils will be vaporized before they encounter a zone having sufficient heat to crack or decompose them. i

To effectively coolthe coke at the lower end of the fuel column, it is necessary that the cool gas entering through the inlet 3S should be distributed throughout the entire area of the fuel column. To accomplish this, the lower end of the fuel column is surrounded by a foraminated apron 122 which is secured to the inner edge of the refractory supporting plate 108 and webs 123 of shell-supporting columns 124. The apron 122 is spaced from the inner surface of the shell and permits gas to enter around the entire periphery of the fuel column. To permit gas to enter the central portion of the fuel column, a central fuel-delecting guide 126 is positioned within the apron 122 and supported on three beams 128 (Figs. 2

and 5), which are secured to the apron 122 and the columns 124. The deflecting guide 126 consists of a cone-shaped member built up of perforated plates which are secured to the beams 128. The outer edge of the guide 126 is spaced from the apron 122 to provide a discharge opening for the coke and a short distance below the discharge opening is positioned a supporting plate 130. The plate consists of an annulus having sufficient width to support the coke emerging from the discharge opening at its angle of repose so that the coke will not run out of the fuel column without being positively removed from the plate. The plate 130 is mounted on I-beams 132 which are secured to the columns 124 for supporting the furnace shell. The coke resting on theV plate 130 is comparatively open so that the heat-transferring gas can enter the fuel column through the discharge opening.

The coke is removed from the supportin plate 130 by a scraper 136 (Figs. 2 and 6? which rests upon the upper surface of the plate and is arranged to be reciprocated across the plate to discharge coke through a central opening 138 in the plate and over the outer edge of the plate. The scraper 136 consists of a circular angle iron which is strengthened by a series of tie-rods 146 connected between an upturned flange of the angle iron and a central block 142. A wear-plate 144 (Fig. 2) is secured to the lower face of the scraper and rests upon a wear-plate 146 attached to the upper face of the plate 130. The scraper is reciprocated across the face of the plate 146 by means of hydraulic engines 148 and 150, which are secured to the outer side of the furnace shell 20 at an angle of 90 with one another. Piston rods 152 connected to pistons of the engines extend through packmg glands 154 on the furnace shell, and the inner ends of the rods 152 are connected by links 156 with a pivot pin 158 secured in the block 142. The engines 148 and 150 are arranged to be operated coordinately to impart a gyratory movement to the scraper 136 and in the gyratory movement the scraper is reciprocated across each part of the Wear-plate 146 and acts to force the coke olf of the plate 130 around its entire periphery. The scraper may be operated contlnuously andv at any desired speed to regulate the llow of fuel downwardly through the furnace.

The coke formed in the choking zone is a dense mass and it sometimes reaches the supporting plate 130 in comparatively large lumps. The webs 123 of column 124 extend through the supporting plate 13() and the thin edge of the webs face the scraper 136 (see Fig. 6). When the lumps of coke are moved outwardly b the scraper 136, the webs 123 assist in breaking the lumps so that the coke will pass through the space between the outer edge of the sup rting plate 130 and the inner face of the urnace shell.

The fuel-charging opening 22 is arranged to be sealed to prevent gas from escaping from the furnace and to prevent air from entering the furnace. To accomplish this the opening 22 (Figs. 2 and 10), is forme in a cylinder 162, the upper end of which is attached to a plate 164 supported upon a hollow column 166 mounted on a top wall 168 of the furnace shell. The space between the cylinder 162 and column 166 is arranged to receive the wall of a liquid sealing pan 170 positioned on the inside of the furnace shell. The sealing pan 170 is supported upon the outer end of a bar 172 which is fixed upon a slidable shaft 174. The shaft 174 is loosel mounted in a bearing 176 attached to t e inner 'face of the furnace shell and passes through a packing box 178 in the top 168. A chain 180 connected to the upper end of the shaft 174 is adapted to be connected with a counter-weight (not shown) to hold the sealing pan 170 in its upper liquid-sealing position, as shown in Fig. 2. To uncover the opening 22, a handle 182 is secured to the shaft 174 by which the shaft may be bodily moved downwardl to withdraw the pan from the opening between the cylinder 162 and column 166, and when the pan is free from the cylinder 162, the shaft may be rotated to move the pan away from the opening.

If fuel is discharged into the opening 22 before the pan has been withdrawn from the opening, it will fall into the pan 170 and interfere with the liquid sealing of the opening. To permit fuel or any forel material to be removed from the pan 1 0, the pan is pivotally mounted upon the end of the arm 172 and the pivot portion of the pan is fixed on a pivot pin 184. An eccentric arm 186 formed on the outer end of the pivot pin 184 is arranged to be projected into one of a pair of slots 188 formed in a disk 190 mounted on the inner end of a shaft 192. The shaft 192 has its inner end loosely mounted in a bearing 194 and its outer end extends through a packing gland 196 mounted in the shell 20. When the pan is drawn down from the cylinder 162, the shaft 192 may be moved inwardly to bring a slot 188 into engagement with the arm 186 and by rotation of the shaft, the pan 170 may be tilted to remove the contents thereof. After the pan 170 has been emptied, it may be again filled with liquid from a pipe 198 (Fig. 10), which passes through the cover 168 and extends into the upper end of the opening between the cvllnder 162 and column 166.

To maintain the gas seal of the opening 22 while fuel is being charged into the furnace, the fuel is charged through the opening b a charging bucket which provides a liqui seal for the opening. The charBging bucket is shown more particularly in i s 9, 10, 11 and 12. The bucket consists o a. cylindrical shell 200 having a closed top 202 and a bottom discharge spout 204. The discharge spout is enclosed within a Sealing flange 206 which is arranged to enter an opening 208 formed between the column 166 and a column 210 surrounding the column 166 and attached to the top 168 of the furnace shell. The space between the columns 166 and 210 is arranged to be filled with fluid by means of a pipe 212 which is connected with the pipe 198. lhen the sealing fiange 206 is in position in the space 208, the discharge spout is located directly above the opening 22 and the sealing pan on the inside of the furnace shell may be removed from the opening 22 without breaking the gas seal of the furnace.

The harging bucket is transported between the furnace and a fuel-illing station while suspended from a bail 214 which is secured to angle irons 216 attached to the top of the bucket. To hold the fuel in the bucket while it is being transferred and positioned over the opening 22, a pair of gates 218 are arranged to close an opening 220 in the spout 204. The gates 218 are mounted on guiderolls 222 which ride on tracks 224 secured within the sealing flange 206 at each side of the opening 220. To permit the gates to be operated for opening and closing the opening 220, rods 226 are secured to one side of the gates 218 and extend through packing glands 228 mounted on the sealing fiange 206. A pair of trunnions 230 are secured at oppositev sides of the Harige 206 to support the bucket in inverted position while it is being filled with fuel.

The coke discharged from the bottom of the fuel column by the scraper 136 is collected in the chamber 24 which has downwardly inclined sides to cause the coke to assemble around a discharge opening 232 (Fig.` 2). When the chamber becomes sufficiently filled with coke, the gate 28 is opened to permit the coke to fall into the chamber 26 and at this time steam may be blown into the chamber through a. pipe 234 to prevent gas from passing down into the chambei' 26 if it should contain air and also to prevent the air from passing from the chamber 26 up into the chamber 24. lvhile the chamber 24 is being emptied, the gate 30 of the chamber 26 is tightly closed to maintain a gas seal for the furnace shell. After the chamber 24 has been emptied, the gate 28 is tightly closed and the coke in chamber 26 is discharged through an opening 236 at the bottom of the chamber. lhile the coke is being discharged from the chamber 26, steam may be blown into the chamber through a pipe 238 to prevent air from entering the chamber.

The coke-discharge gates 28 and 30 and the mechanism for operating them have substantially the same construction. The gates consist of plates which are hin ed to frames 240 and 242 secured respective y around the openings. 232 and 236 of the chambers 24 and 26. The mechanism for operating the discharge gates is arranged to swing the gates into and out of position over the discharge openings and to positively force the gates into as-sealing engagement with a knife edge ormed on the lower end of the frames. The mechanism for operating the gates is best shown in Figs. 7 and 8 and may be described as follows: A yoke 244 is pivoted at opposite sides of the frame 240 and is pivotally connected with a pressure link 246 which is pivoted to the discharging gates. A driving rod 248 is connected to the common pivot of the yoke and link and extends upwardly to an operating shaft 250. The lower face of the rod 248 is provided with a rack 252 which engages a pinion 254 fixed on the shaft 250. The shaft 250 is journalled in brackets 256 secured to the inclined face of the coke chambers `and a hand-wheel 258 is fixed on the outer end of the shaft. To hold the rack 252 in engagement with the pinion 254, a guide-rod 26() is secured to the rod 248 and passes below the shaft 250. The yoke 244 and pressure link 246 form a toggle for forcing the cover into engagement with the frame 240 and by adjusting the length of the link 246, the pressure of engagement of the gate with the frame may be varied. When the parts are in the position shown in Fig. 7, the toggle is straightened and the gate is in pressure engagement with the frame. Upon the first part of the movement of the rod 248 by the hand-wheel 2.3() to remove the gate from the discharge opening, the toggle is broken to release the gate and a further movement of the rod tends to swing the gate about its hinge.

With the improved furnace construction described above, coal may be continuously carbonized and distilled with a minimum expenditure of fuel for producing the necessary heat. The vapors evolved from the distillation of bituminous coal condense as a mobile dark brown liquid, which is referred to above and in the claims as oil or "tar`". This mobile li uid contains aromatic or benzene hydrocarllcons and is much more valuable as an oil than if it were dissociated into fixed gases and carbon. By avoiding the dissociation of the primary distillation products, the oils condensed contain practlcally no fixed carbon and may be removed from the furnace as mobile liquids as distinguished from the heavy viscous tars formed in the ordinary gas bench and by-product coke ovens.

The withdrawal of the heavier oils near the lower portion of the coal-distilling zone permits the oils to be recovered without being dissociated and maintains the porosity of the fuel bed so that the heat-transferrin gaseous medium may be circulated throng the bed at a comparatively high velocity. Vith a high velocity gas circulation, the transfer of heat between the fuel and gas is more rapid and the gas carries the distillation products away from the heating zone before they are dissociated.

Further, the improved furnace construction permits the volatile constituents of coal to be gradually and uniformly distilled off so that the coke is compact and dense. The construction also permits a comparatively high temperature to be maintained in the localized coking zone to consolidate the coke and drive ofi' the last portion of volatile material while still having a comparatively low temperature in the distilling zone to gradually remove the volatile constituents.

The preferred form of the invention hav ing been thus described, what is claimed as new is:

1. A coal carbonizing furnace having in combination an upright metal shell, a refractory lining mounted around the inner periphery of the middle portion only of the shell, a gas olf-take at the upper end of the shell, a closable fuei charging opening at the upper end of the shell, mechanism for removal of material from the bottom of the shell, and a gas distributing means mounted in the shell near its bottom arranged to introduce a combustion supporting gas into a column of fuel in the shaft adiacent the refractory lined portion.

2. A coal carhonizing furnace having in combination an upright metal shell, a refractory lining mounted around the inner periphery of the middle portion only of the shell, a gas off-take at the upper end of the shell, a closable fuel charging opening at the upper end of the shell, a coke discharging device positioned near the bottom of the sheli, power operating means for operating said device to control the movement of fuel through the shell, a gas distributing means mounted in the shell near its bottom arranged to introduce a combustion supporting gas into a column of fuel in the shaft adjacent the refractory lining, and a pump for controlling the circulation of the combustion supporting gas through the distributor into the fuel column.

3. A coal carbonizing furnace having in combination an upright metal shell, a refractory lining in the shell, a closable fuel charging openlng at the upper end of the shell, mechanism for the removal of material from the bottom of the shell, a gas and vapor off-take at the top of the shell, a gas distributing means positioned in the shell near its bottom arranged to introduce combustion supporting gas into the mid ortion of a column of fuel in the shell, and) separate vapor and liquid outlets connected to the shell adjacent its mid portion.

4. A coal carbonizing furnace having in combination an upright metal shell, a refractory lining in the shell, a closable fuel charging opening at the upper end of the shell, a mechanism for the removal of material from the bottom of the shell, a gas and vapor off-take at the top of the shell, a gas distributing means mounted in the shell near its bottom and a'rranged to introduce combustiolr supporting gas into a fuel column in the shell, tar collecting chambers mounted in the inner surface of the shell adjacent the mid portion thereof and draw off outlets connected with said tar chambers.

5. A coal carbonizing furnace having in combination an upright metal shell, a refractory lining in the shell, a closable fuel charging opening at the upper end of the shell mechanism for the removal of material from the bottom of the shell, a as and vapor off take at the top of the shelf, a gas dstributer mounted in the shell near its bottom arranged to introduce gas into a column of fuel therein, connections between the gas off-take and the distributor, an air in-put pipe in the said connections and blowers for controlling the volume and velocity of circulation of air and gas through the connections and the shell.

6. A coal carbonizing furnace having in combination a gas tight shell, a closable fuel charging opening at the upper end of the shell, mechanism for the removal of material from the bottom of the shell, a gas off-take at the top of the shell, a gas distributer mounted in the bottom of the shell having means for supporting the fuel column, means for permitting gas to enter directly into the fuel column through the bottom and around the periphery of its lower portion, and means to circulate gas through the distributer and the shell.

7. A coal carbonizing furnace having in combination a vertical gas-tight shell, a refractory lining in the mid-portion of said shell, a tar4 collecting chamber arranged in said shell above said lining, means to admit tar to said chamber, means to withdraw tar from said chamber, and means for withdrawing gas and coke from said shell.

8. A coal carbonizing furnace having in combination a gas `tight shell, a refractory lining in the shell, a closable fuel charging opening at the upper end of the shell, mechanism for the removal of material from the bottom of the shell, a gasand vapor out-take at the top of the shell, and a distributer po'` sitioned in the shell near its bottom comprisi a perforated apron at the bottom of the rrgractory lining arranged to. surround a column of fuel in the shell 'and spaced from the inner wall of the shell, a perforated supporting plate positioned `wlthin and spaced from the apron, an annulus plate po sitioned a substantial distance below the space between theapron and the supporting plate and a gas inlet connected with the shell adjacent said distributor.

9. A coal carbonizing furnace having in combination, a gas-tight shell, means to support a column of fuel in said shell, means to maintain a hot mid-zone and cool ends in said column, a pluralityof tar-collecting chambers arranged in said shell adjacent said mid-zone, means to admit tar and gas into said chambers, means to withdraw gas and tar from one chamber, and means to withdraw tar from the other of said chambels.

10. A coal carbonizing furnace having in combination, a gas-tight vertical shell, means for circulating a gaseous heat-transferring medium through said shell, means to support a column of fuel in said shell in position to introduce said gaseous medium underV a substantially uniform pressure through a substantial portion of the bottom and around the periphery of said fuel column, and means to Stir up'and remove coke from the bottom of said fuel column adjacent the inlet of gas into said column.

11. A coal carbonizing furnace havin in combination, a gas-tight vertical s ell,

means for charging fuel into said shell and for removing coke from said shell, and a support for a column of fuel in said shell comprising an annulus plate positioned near the bottom of said shell with its outer edge spaced from the inner face of said shell and a central deflector mounted above said plate.

12. A coal carbonizing furnace having in combination, a vertical gas-tight shell, a central deflector mounted near the bottom of said shell, an apron surrounding and spaced from said deflector to leave a discharge opening for coke and spaced from the inner Wall of said shell to provide a gas passage, an annular plate supported below said dlscharge opening, a scraper on said plate, and means to impart a gyratory movement to said scraper to reciprocate the scraper across each tion of said late.

13. A coa carbonizing furnace having in combinatlon, a gas-tight shell, a support for a column of fuel in said shell comprising an annular plate having its outer edge spaced from the inner face of the shell and arranged to receive fuel discharged from said fuel column, a scraper on said plate. and means to reciprocate said scraper across each part of the central portion of said plate.

part of the central por- 14. A coal carbonizing furnace having in combination, a gas-tight shell, a support for a column of fuel in said shell comprising an annular plate having its outer edge spaced from the inner face of the shell and arranged to receive fuel discharged from said fuel column, a scraper on said plate, and a pair of separately operated driving means mounted at an angle to one another and connected with said scraper to simultaneously operate on said scraper for imparting a discharging movement thereto.

15. Acoal carbonizing furnace having in combination, a gas-tight shell, a support for a column of fuel within said shell comprising an annular plate having its outer edge spaced from the inner face of the shell and arranged to receive fuel from said fuel column, a scraper on said plate, and means for operating said scraper com rising pistons mounted on Said shell at `right angles to each other, and means for connecting said pistons to a common point on the scraper.

16. A coal carbonizing furnace having in combination, a gas-tight shell, a liquid-seal chargingopening for said shell, means for supporting a colmun of fuel in said shell, means for continuously moving fuel through said shell, a valve discharge coke-collecting chamber, and a valve discharge coke-discharging chamber.

17. A coal carbonizing furnace having in combination, a gas-tight shell, means for continuously carbonizing fuel in said shell, means for continuously withdrawing gas from said shell, a fuel-charging opening in said shell, means for sealing said charging opening from the inside and from the outside of said shell, and a gas-sealed coke-discharging opening for said shell.

18. A coal carbonizing furnace having in combination, a gas-tight shell, a sealed charging opening for said shell, means for carbonizing coal in said shell, an enclosed coke-collecting chamber at the bottom of said shell, an outside coke-dischar ing chamber for receiving coke from the col ecting chamber, discharging devices for said chambers, and means for operating said devices.

19. A coal carbonizing furnace having in combination, a gas-tight shell, a gas-sealed fuel-discharging opening, a coke-collecting chamber and a coke-dlscharging chamber having inclined bottoms, and means for removing coke from said chambers comprising dischar e openings therein, a pivoted gate for sai openings, and means for operating said gate arranged toswing said gate on said pivot to press said gate into gassealing relation with said openings.

20. A coal carbonizing furnace having in combination, a as-tight shell, a gas-sealed fuel-charging evice, a coke-discharging chamber having an inclined bottom, and means for removing coke from said chamber comprising a discharge opening in said chamber, a gate pivoted to said bottom, a yoke pivoted to said bottom, a pressure link connected between said yoke and said gate;

and means for operating said yoke and link.

21. A coal carbonizing furnace having in combination, a gas-ti ht shell, means to support a column of fuein said shell, means to maintain a hot mid zone and cool ends in said column, a plurality of tar-collecting chambers arranged in said shell adjacent said mid zone, means to admit tar and vapors into said chambers, and means to separately withdraw gas and tar from said chambers.

In testimony whereof I aflix my signature.

HENRY L. DOHERTY.

Certificate of Correction.

1t is hereb certified that in Leiters Patent No. 1449,591 granted March 27. 1923, upon t e apglication of Hen-rv L. D herty, of New ork, N. Y., for an improvement in J tion requiring correction as fo lows: Page 2, line 32 after the word fue] insert the words of the column or b page 8, line 53, claim 19, for the com und word fuel-discharging read f1 charging; and that. the said Letters stent should be read with these corrections therein that the same may conform to the record of the case in the Patent Olce.

Signed and sealed this 11th dav of September, A. D., 1923.

[am] KARL FENNING, Acting Camwomr of Patents.

oel-Carbonizin Furnaces, errors appear in he printed speci- 

